In this unit students explore and develop proficiency in creating and using models to understand reflection, absorption, and transmission of sound, a type of matter wave. Students will engage in five lessons. In Lesson One students conduct research and develop empathy around noise-induced hearing loss, or NIHL, to understand the effects of sound intensity on hearing. Lesson Two explores transmission, absorption, and reflection of sound within written scenarios and through modeling different “Noise Capsules.” In Lesson Three, students focus there learning on sound transmission through various materials by building sound boxes. Students use reflection in Lesson Four to gain first-hand experience with echolocation. The unit culminates with a design challenge in Lesson Five, where students demonstrate proficiency for the concepts of reflection, absorption, and transmission of matter waves by designing, building, and testing a noise cancelling device.

Educational outcomes

Lesson One – Learn about sound intensity and its effects

Lesson Two – Develop and use noise capsule models to describe transmission, absorption, and reflection of sound by various materials

Lesson Three – Develop and use sound box models to explore transmission of sound through various materials

Lesson Four – Use a model to experience the reflection of sound off various materials to locate objects

Lesson Five – Develop and use a model to determine and then present how to minimize the effects of excessive noise on NIHL for local residents

STEAM INTEGRATION

Lesson One requires students to measure sound intensity, which is directly related to sound wave transmission (MS-PS4-2). Lessons 2-4 involve the development of models from various materials to explore and analyze the transmission, reflection, and absorption of sound (science and engineering). This allows for an exploration of material properties similar to investigating a medium used by an artist. Lesson Five requires students to apply all learning from previous lessons to develop and test a model in order to answer an inquiry question and then present the results to make a recommendation for ways people can protect themselves from NIHL (SL.8.5).

Maker Journal Pages

Design Thinking Overview

Our design thinking units have five phases based on the d.school’s model. Each phase can be repeated to allow students to re-work and iterate while developing deeper understanding of the core concepts. These are the five phases of the design thinking model:

EMPATHIZE: Work to fully understand the experience of the user for whom you are designing. Do this through observation, interaction, and immersing yourself in their experiences.

DEFINE: Process and synthesize the findings from your empathy work in order to form a user point of view that you will address with your design.

IDEATE: Explore a wide variety of possible solutions through generating a large quantity of diverse possible solutions, allowing you to step beyond the obvious and explore a range of ideas.

PROTOTYPE: Transform your ideas into a physical form so that you can experience and interact with them and, in the process, learn and develop more empathy.

TEST: Try out high-resolution products and use observations and feedback to refine prototypes, learn more about the user, and refine your original point of view.

Lessons 1-4 can all be taught as individual learning experiences that explore sound transmission, absorption, and reflection. Lessons 1-3 make use of the same smartphone app to measure sound intensity.

In this lesson students develop empathy by learning about the effects of various sound intensities on hearing. They will conduct research to learn about noise-induced hearing loss (NIHL) and the sources of excessive sound that increase one’s chances of having the condition with prolonged exposure. Students learn about sound intensity and how it is measured. Students use a smartphone or iPhone application to measure and record sound intensity in their own community at different locations and identify the sources. They will compare measured noise levels to those addressed by local ordinances designed to regulate sound intensity caused by certain sources. Students use their measurements, comparisons, and research to formulate a hypothesis for the need to monitor or control noise levels to reduce the risk of NIHL in the community.

Essential Questions:

What is noise-induced hearing loss, or NIHL, and what causes it?

What is sound intensity and how is it measured?

Why must people be concerned about sound intensity in the community?

LESSON PROCEDURE:

Students conduct web research and identify resources with information on NIHL and sound. Monitor students to ensure they access appropriate websites.

Students record each source and information they find in the Maker Journal page.

Make sure students practice using the calibrated sound meter apps before conducting the steps below.

Students identify 10 different locations in their local community in which to measure and record sound intensity. Some suggestions for locations are areas in or around airports, shopping centers/malls, libraries, schools, and hospitals. Students record the specific locations, times, and sound measurements in the Maker Journal Page.

Students identify local ordinances or laws, if any, that are intended to regulate noise levels and then compare them to the measured sound intensity data.

Students use their data and findings to formulate their own hypothesis for the need to monitor or control noise levels and how to reduce the risk of NIHL in the community.

T: “Which of these two places do you think is the loudest, a crowded shopping mall or a busy airport? Explain your thinking.”

S: “Planes are louder than people.” “Malls have loud people in them!” “They are about the same noise level.”

T: “We are going to conduct web research to find information on noise-induced hearing loss, or NIHL. Then you will use an app to measure sound intensity in the community. Which websites might provide the best information?”

Matter waves areprogressivedisturbancespropagated frompointtopointinamedium (matter)without progressoradvancebythepointsthemselves,as inthetransmissionofsound. Matter waves require a medium in order to propagate whereas light, or electromagnetic waves, do not require a medium (can move through a vacuum). All waves have the properties show below. The amplitude of a wave is the maximum extent of a vibration or oscillation, measured from the position of equilibrium. These are the crests and troughs of a wave. The wavelength is the distance between successive crests of a wave. The frequency of a wave is the rate at which the crests or troughs reach or pass a certain point t per second (see below). Frequency is usually measured in Hertz (1 Hz = 1 wave per second).

Sound intensity is often measured in decibels, which in the general use of the word is a degree of loudness. Breathing is typically around 10 decibels and is barely audible, whereas a library or typical bird calls are around 40-45 decibels. A thunder strike or jet plane take-off are extremely painful and can rupture ear drums!

External Resources

Maker Journal Pages

Teacher Notes

Make sure students follow the procedure for calibrating the sound meter app before taking any measurements! The calibration protocol can be accessed within the help section of the app once installed.

Active Classroom

Communication is critical in the design process. Students need to be allowed to talk, stand, and move around to use and acquire materials, including technology. Help students become successful and care for the success of others by asking them to predict problems that might arise in the active environment and ask them to suggest strategies for their own behavior that will ensure a positive working environment for all students and teachers.

Learning Targets

Students use a model (within a sound application) to describe that waves are reflected, absorbed, or transmitted through various materials

Students review the properties of matter waves and that matter waves need a medium through which to be transmitted

Assessment

Student Self Assessment

Students compare their own sound intensity measurements with known measurements from the same sound source. For example, if a students recorded intensity in a crowded shopping mall, he or she could look up the average intensity in decibels for a shopping mall or similar place.

Peer Assessment

Student groups discuss and compare their hypotheses on the need to monitor or control noise levels in certain places within the community where measurements were conducted.

Teacher Assessment

Check Maker Journal pages for measurements, answers to questions, and a hypothesis based on the findings of each group. Provide feedback as necessary.

Students engage in a design activity where they build three capsule-like devices according to certain criteria and constraints that hold a small object (action figure, egg, etc.). Students will drop each capsule over multiple trials and measure the sound output with a sound meter app to identify the capsule, and thus specific materials, that produce the least sound. Differences in sound output will be described in terms of reflection, absorption, and transmission (MS-PS4-2).

Essential Questions:

What are some examples of objects that reflect, absorb, or transmit sound?

How does the type of material play a role in the amount of sound transmitted, absorbed, or reflected by an object that strikes the floor?

LESSON PROCEDURE:

Students collaborate and build three (3) different capsule-like containers into which to put an object of choice (egg, action figure, or other).

The capsules must be built to meet the criteria and constraints specified in the Maker Journal Page.

After the capsules are built, students will test each one by dropping it from a specified height and measuring the sound produced when it collides with the floor using the sound meter app.

Students record their sound measurements. They answer the questions and reflect on their capsule designs.

Students identify the capsule that was the least noisy based on the data and relate this to the materials used to build it.

Students discuss the test results and describe instances where sound was absorbed, reflected, and/or transmitted through materials, including the floor.

T: Give students this scenario, “Suppose I have two rocks. If I put one of them in a container made mostly of foam and the other rock in a container made mostly of plastic, which one will make the loudest sound when dropped to the floor?”

S: “The one with foam because it will make a slapping noise.” “The plastic because it will create a loud bang.” “Foam insulates, so maybe it will be quieter.”

T: Today you will explore reflection, absorption, and transmission of sound by building “noise capsules”, much like the containers we just talked about. You will build and drop them and take measurements of the noise levels they produce.

S: “Will we be told how to build them?”

T: “No. You will work in teams and choose materials to build with. Just make sure the capsules you build are made with different materials so when you measure the sound outputs you can make good comparisons and explore how the materials are related to the measured outputs.”

Waves represent a propagation, or widespread movement, of energy. When waves come into contact with a material the energy is either absorbed, reflected, or transmitted through the material. Which interaction occurs depends on the type of material. When a wave is able to transfer all of its energy to a material, the interaction is called absorption because the energy is received by the molecules that make up the absorbing material. If the wave energy is bounces away from the material after contact, the interaction is called reflection. Transmission happens when the wave’s energy is allowed to pass through the material.

Imagine you are standing in a room with no drywall, flooring, or roof materials. Sounds generated in the room will reflect off the wood and bounce around the room and likely take many minutes to die out. Now suppose there are walls, flooring, and a good roof. The sound may still bounce around but it is likely the sound will be partially absorbed by the surrounding materials. The sound will dampen, or reduce, faster as some of the wave energy is transferred to the materials. Now suppose someone is making noises outside the room. If you hear the noise then the wave energy, or at least part of it, is transmitting through the walls. In reality these three interactions occur simultaneously within a system.

Active noise control (ANC), also known as noise cancellation, or active noise reduction (ANR), is a method for reducing unwanted sound by the addition of a second sound specifically designed to cancel the first. Another method of controlling sound is soundproofing. This involves reducing the sound pressure with respect to a specified sound source and receptor. This can be done using a variety of materials that absorb or reflect sound waves. The picture below shows a room with soundproof walls.

Maker Journal Pages

Teacher Notes

Materials:

Place materials on a table or cart that is accessible from two or more sides to facilitate flow while students choose materials for building. Make sure that each material is visible and any bundled items are separated.

Testing:

The capsule testing should be as consistent as possible. Encourage students to consider dropping the capsules from the same height and in the same spot for each test. They should also consider keeping the sound measuring device stationary during the tests.

Technical:

Sound meter apps installed on devices should be calibrated before starting the lesson. The app can be calibrated following the instructions listed in the Help section of the app interface.

Active Classroom

Communication is critical in the design process. Students need to be allowed to talk, stand, and move around to acquire materials. Help students become successful and care for the success of others by asking them to predict problems that might arise in the active environment and ask them to suggest strategies for their own behavior that will ensure a positive working environment for all students and teachers.

Practice and predict clean-up strategies before beginning the activity. Ask students to offer suggestions for ensuring that they will leave a clean and useable space for the next activity. Students may enjoy creating very specific clean-up roles. Once these are established, the same student-owned strategies can be used every time hands-on learning occurs.

Learning Targets

Students will engage in the design process

Students will describe sound output differences in terms of reflection, absorption, and transmission

Assessment

Student Self Assessment

Student groups review their Maker Journal and summarize their learning in a group discussion. They should focus on their measurements and relate them to the materials in each capsule.

Peer Assessment

Student groups discuss and compare their findings and elements of their noise capsule designs.

Teacher Assessment

Review student Maker Journal pages for formative assessment and discuss with individual groups as they work.

Conduct a whole group discussion to allow all students to share, discuss and compare their results. They explain their findings in terms of the interaction (absorption, reflection, and transmission) between the sound generated by the impact with the floor and the materials used to build each capsule.

Students explore the transmission of sound through different materials that are placed inside of a simple sound box. They place a sound source inside the box underneath the materials to be tested and then measure the sound output with a sound meter app (MS-PS4-2).

Show students how to properly overlap the binder covers (see picture below).

Students apply binder clips around overlapped covers to secure both binders in the shape of a box.

Create a bottom for the box either by wedging a material (like foam) in between the sides of the box or by wrapping material around the bottom edges of the box. The goal is to create a “container” into which the sound source and materials to be tested will be placed.

T: Show students this megaphone image. “Here is a megaphone emitting sound. Which of these two materials, the packing peanuts or insulating foam, do you think will transmit the least amount of sound? Why?”

S: “The packing peanuts because the sound will touch more of them.” “The insulating foam prevents heat transfer, so maybe it will block sound, too!” “The foam is not as hard so more sound will get through it.”

T: “Today you will build assemble a simple sound box in which to put a sound source and different materials. Then you will measure the sound output through the materials to see which one transmits the least sound.”

S: “What are the steps for testing each material?”

T: “The steps are outlined in the Maker Journal page for this lesson. Follow them and ask for help when needed. I suggest you test one material at a time and be consistent with how you measure the sound output. That way your readings will be more valid.”

Transmission occurs when the energy carried by a wave is allowed to pass through a material. Some energy is usually absorbed by the molecules in the material, leading to a reduction of energy transmitted through a material. In physics this is called attenuation. An example of attenuation with sound waves is hearing music through a bedroom wall. In the bedroom the sound is loud but outside it is relatively quieter because the wall material absorbs and reflects some of the energy. The sound waves are carrying less energy as they pass through the wall, which is perceived as lower volume when heard (see below). Soundproofing involves the use of materials to reflect and/or absorb sound such that it cannot escape the defined space. Recording studios are examples of soundproof spaces because each studio is made with materials that allow one artist to sing and record his or her songs without disturbing people in adjacent studios.

The amount of attenuation depends on the material through which sound is passing. The sound box provides a consistent testing tool with which to test the amount of transmission of sound through various materials and allows students to draw logical conclusions about the properties of certain materials in terms of transmission, absorption, and reflection of sound.

Peer Assessment

Teacher Assessment

Review student Maker Journal pages for formative assessment and discuss with individual groups as they work.

Conduct a whole group discussion to allow all students to share, discuss and compare their findings around materials that provided the least amount of sound transmission and then explain them in terms of attenuation and the properties of the materials that were tested.

Students experience what it is like to rely on sound to identify where an object is by listening to sounds being reflected from walls within a defined space (MS-PS4-2).

Essential Questions:

What is echolocation?

What types of materials in a space reflect the best sound?

LESSON PROCEDURE:

Students use a cloth or paper strip to make blindfolds, making sure they can be tied or fastened behind the head.

Students draw the room, taking into account fixtures on the walls, the general shape of the space, the materials each wall is made from, and the presence of windows, curtains, or blinds.

Student groups choose a team observer to be blindfolded and position that person at one end of the room.

They turn the sound source on and place the it at least 10-15 feet away from blindfolded person.

Students indicate the position of the sound source for the first round in their room drawing.

Students start a stopwatch and the blindfolded observer begins to walk slowly towards where he or she perceives to be the position of the sound source. If there is a danger of colliding with something or falling, students can say “STOP” and guide the observer around the obstacle and then continue the round.

When the observer reaches the sound source, the elapsed time is recorded and the observer goes to the same starting position as before.

Student groups choose a teammate to hold the sound source. The blindfolded observer goes to the starting position and tries to move towards the sound source. The person holding the sound source moves about the space slowly. The goal here is to see if the observer can track the sound as it moves. Note: The sound source person should not be purposely trying to avoid or trick the observer!

Students repeat the procedure so each person on the team has been the observer at least one time.

T: “In this lesson you will “see” like a bat by using reflected sound to find a sound source. Do you know what this ability that bats have is called?”

S: “I think it is sonar.” “Is it echolocating?” “It’s ultrasound!”

T: “I will review the procedure with you and then you will work with your group and measure the time it takes to locate the sound source while blindfolded!”

S: “Who will be blindfolded? Will we all do this or just one person in the group?”

T: “Each person in the group will get a turn to be blindfolded. That person, the observer, will locate the sound source under two different conditions. First the sound source will be stationary, not moving. Then it will be held by another person in the group who will then walk around slowly.”

Echolocation is the location of objects by reflected sound, in particular that used by animals such as dolphins and bats. It is a type of biological sonar that allows animals that use it to find prey items as well as communicate with others in the species. For example, bats emit ultrasonic sounds in flight, usually in total darkness, allowing them to locate and hunt insects and also avoid obstacles while flying. They are moving and adjusting course as needed as are the insects they eat. In this lesson, students move around a space such as a room or hallway in order to locate the position of a sound source. The sound source remains stationary to start with in order to model how bats locate stationary prey items. Moving the sound source around models a situation where echolocation is used during flight to find a moving prey item. The materials that make up the walls of a space directly impact the amount of reflected sound experienced by an observer in the space.

In the graphic below, the bat emits a sound (E) that travels over a distance (d) towards the butterfly (B). The sound reflects back towards the bat (R), allowing the bat to know the location and distance to the butterfly.

Lesson Materials

Building Materials

Notepad or graph paper

Cloth or paper to make blindfolds

Tech

Sound source (mp3 player, small radio, or equivalent device)

Other

Stopwatch or equivalent

Maker Journal Pages

Teacher Notes

Make sure that the space for the activity is clear of obstacles such as furniture, cords, overturned rugs, and also block areas leading into stairwells or sudden drops. Monitor student groups to ensure the students conduct teh activity safely.

Blindfolds: The cloth or paper should be cut into 2″ x 24″ strips

Learning Targets

Students will use the activity as a model to describe that waves are reflected by various materials

Assessment

Student Self Assessment

Students review their location times for both moving and stationary conditions and then develop a testable hypothesis for how to improve the times using different reflective materials.

Peer Assessment

Student groups share their reasoning for why having a moving sound source was more challenging than a stationary source.

Teacher Assessment

Conduct a whole group discussion to allow all students to share, discuss and compare their findings around different materials in the room that reflected sound and explain the average times recorded by the group.

In the culminating project, student groups demonstrate their knowledge of reflection, absorption, and transmission of matter waves by designing, building, and testing a noise cancelling device. They engage in each step of the design process and reiterate multiple times until their group agrees the device meets the defined criteria and constraints for the project (see design challenge introduction). Students develop a presentation where they explain how their device addresses the design problem.

Essential Question:

How can the properties of different materials be used to build a noise cancelling device that minimizes the effects of excessive noise on noise-induced hearing loss (HIHL) for local residents?

LESSON PROCEDURE

Students facilitate a brainstorm in their groups to generate approaches to answer the essential question.

Student groups agree on an idea from the brainstorm and then select materials with which to build their first prototype.

Students build a prototype according to the criteria and constraints defined in the design challenge introduction (see section below).

Students test their first prototype using the checklist provided in the Maker Journal page, noting any changes or modifications that must be made.

Students reiterate, repeating the process until the group agrees that the device successfully meets the criteria and constraints.

Student groups demonstrate how their devices minimize noise to acceptable levels and addresses the design problem based on their research conducted in Lesson One (empathy phase).

T: Introduce the design problem: “Today you will be combining the learning from the previous lessons on absorption, reflection, and transmission of sound waves to solve a problem through design. Here is the problem: How can the properties of different materials be used to minimize the effects of excessive noise on noise-induced hearing loss (HIHL) for local residents?”

S: “That sounds like a tough problem. How will we do that?”

T: “Essentially what you are tasked with building is a noise cancelling device. There are many designs for such a device, but keep in mind it must be useful for local residents. You measured sound outputs in different places during the first lesson, so think about the types of noises that must be cancelled and how you might do that with various materials. Would you make a room soundproof? Would you use something to reflect sound around objects? Explore all possibilities!”

S: “I think we can come up with cool ideas!” “Let’s get started!”

Criteria & Constraints

Review the criteria and constraints with students. Engineers design things using some rules about how the designs must behave or work. These rules are called criteria. Engineers can run out of materials, money, time to build, or space in which to build something. In other words there are limits on how something can be built. These limits are called constraints. The criteria and constraints for this challenge are below.

Criteria (design requirements)

Constraints (design limitations)

Model significantly reduces sound (by 20-30%)

Model includes elements that transmit, reflect, and absorb sound

Model is portable

Model must be built with materials provided

Model must be completed and tested in the given time

Model must include at least 8 different materials in addition to fasteners and/or adhesives

Model must be less than 2 feet wide along any dimension

IdeateStudent groups will leverage their learning on sound waves and NIHL to brainstorm and sketch ideas for the noise cancelling device and methods for testing it against the defined criteria and constraints. Students may choose or need to return to this phase as the iterate.

T: “Some of you may spend too much time figuring out how to start. Be sure to get something built quickly so that you have a real version of the idea you started with. Engineers call this rapid prototyping. Your first iteration will not be the best or final one, so don’t be too concerned with making it perfect!”

S: “I want it to work the first time.” “How will we know if it works well?”

T: “You will test the prototype once your group agrees it’s ready. You will check to see if it meets the criteria and constraints and most likely come back to prototyping based on what you learn through testing. This is what iteration is all about.”

S: “Oh, this means we will build more than once. I get it. It’s a cycle!”

Prototype

Student groups choose materials and begin build the first iteration of their noise cancelling device based on an idea generated during the ideate phase. Keep in mind students may choose to or need to return to this phase as the iterate further.

T: “You will need to test your design against the criteria and constraints to ensure the device works properly and can be used to address the design problem. The checklist in the Maker Journal page will provide a quick way to evaluate your design. Be sure to record everything you observe.”

S: “When will we start testing?”

T: “Your group will test the prototype as soon as you all agree it is ready to be tested. I do not need to tell you when to start. Make sure you are consistent in the way you evaluate your design for each test. Also, be sure to calibrate the sound measuring equipment before you measure and record any sound data.”

S: “How will we know when to stop testing? When is the design final?”

T: “When your group agrees the noise cancelling device meets all criteria and constraints and has been improved as much as possible in the time given, you can stop. I may ask questions or make suggestions for things that can be added or modified and, if time permits, you may decide to address them.”

Test your Design

Student groups test their designs for the ability to meet all criteria and constraints using the checklist in the Maker Journal page. They record their observations for each test and use the data to refine the design as they continue to iterate.

T: Provide a general description of what students will do during and after the design challenge. “You will be engaging in each of the steps of the engineering design process in order to solve a design problem. The steps of the process are ideate, prototype, and test. We’ll go through these steps many times to produce the solution to the problem. After you develop the final iteration, or updated version, of the solution, your group will present the solution to the class.”

S: “How will we know what goes into the presentation? What do you want in a good one?”

T: Review the presentation rubric with students. “The rubric describes levels of quality for different elements of the presentation. Basically, you need to make sure you describe how your solution solves the design problem, how it demonstrates reflection, absorption, and transmission of waves, and in the process you use the concepts learned in previous lessons. This includes the properties of waves, e.g. amplitude, frequency, and wavelength.”

This design challenge allows students to engage in the engineering design process. This process can be represented in many ways. People may engage in the steps in any order. This unit is built around a model with five design phases: empathy, define, ideate, prototype, and test. Engineering is an iterative discipline with many design steps being taken several times. This is why there are so many versions of televisions, toothbrushes, and many other common items. Each product is intended to serve a particular purpose and meet the needs of specific users.

This specific design challenge focuses on sound as an example of matter waves provides students with an opportunity to combine knowledge of wave properties with the concepts of wave reflection, absorption, and transmission through various materials. Students develop a real solution for the problem of minimizing the effects of excessive sound on the occurrence of noise-induced hearing loss (NIHL). This is the real-world connection that circles back to the empathy lesson where students conducted research on NIHL and investigated sources of sound in their local areas that must be minimized or controlled.

External Resources

Maker Journal Pages

Teacher Notes

Materials: Place materials on a large table or cart that is safely accessible to all student groups. Send 1-2 students from each group to gather materials to facilitate efficient use of time and prevent a bottleneck.

Presentations: Be sure to review and provide copies of the rubric to students. They can use it for developing a high quality presentation.

Active Classroom

Communication is critical in the design process. Students need to be allowed to talk, stand, and move around to acquire materials. Help students become successful and care for the success of others by asking them to predict problems that might arise in the active environment and ask them to suggest strategies for their own behavior that will ensure a positive working environment for all students and teachers.

Practice and predict clean-up strategies before beginning the activity. Ask students to offer suggestions for ensuring that they will leave a clean and useable space for the next activity. Students may enjoy creating very specific clean-up roles. Once these are established, the same student-owned strategies can be used every time hands-on learning occurs.

Learning Targets

Students will develop and use a model to describe that waves are reflected, absorbed, and transmitted through various materials.

Assessment

Student Self Assessment

Students review their Maker Journal page for evidence that they understand the properties of waves and can individually explain where in the group model waves are being reflected, absorbed, and transmitted.

Peer Assessment

Allow student groups to conduct a “gallery walk” where they explore and learn about each other’s models.

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